1. Field of the invention
The invention relates to a TEM waveguide arrangement.
2. Discussion of Background
The invention refers with the preamble of patent claim 1 to a prior art as disclosed in EP-A1-0 246 544. A reflection-free termination is specified there for a TEM waveguide, in which a TEM wave is guided between an inner conductor and an outer conductor. Provided as line termination for the purpose of absorbing conductor-bound energy is an ohmic resistance which effects a gradual, serial damping of the inner conductor and locally compensates a capacitance per unit length additionally caused by RF absorbers for absorbing field-bound energy. Such TEM waveguide arrangements or waveguide cells serve to test electronic devices for their compatibility with reference to an external effect of electromagnetic fields, and to conduct broadband emission measurement, Defined field distributions can be set over a wide frequency range.
A disadvantage is the large outlay on parallel and series circuits for the terminators.
EP-B1-0 363 831 discloses a TEM waveguide arrangement having a TEM waveguide which widens in the shape of a pyramid and which has an asymmetrically arranged, plate-shaped inner conductor. The latter is led through an absorber wall, which is curved in the manner of a calotte, or hemispherical shape, and has pyramidal radio-frequency pointed absorbers, to a number of terminators. It is not possible at input powers above 1 kW for the heat produced at the termination of the inner conductor to be adequately dissipated. The compensation of the capacitance per unit length caused by the RF absorbers is unsatisfactory. Because of their method of production, the absorbers have excessively large tolerances in the range of .+-.50%.
For the relevant prior art, reference may also be made to a company brochure: The Carborundum Company, Electronic Ceramics Division, P.O. Box 664, Niagara Falls, N.Y. 14302, Form A-7049, dated 1981, which discloses low-inductance, tubular resistors which withstand temperatures up to 230.degree. C. or 350.degree. C. and peak voltages of up to 5 kV.